Patent GB-675064-A (GB)
Title: Drilling machine
IPC: E21B44/02
Filed: 1950-05-25
Abstract: 675,064. Machines for drilling rock &c. CONSTRUCTIONS ELECTRO-MECANIQUES DE ST.-ETIENNE ANCIENNE USINE WAGEOR.. May 25, 1950 [May 27, 1949], No. 13135/50. Addition to 657,310. Class 83 (iii). [Also in Group XXXVII] A drilling-machine of the type described in the parent Specification, which comprises main and auxiliary electric driving motors, the latter being reversible and having a high rotor slip in order that the feed motion may be automatically varied according to the hardness of the material being drilled, is characterized in that it comprises an elongated stationary frame in which rotates the feed shaft and along which moves a carriage in which the drill and feed shafts are journalled, said carriage also carrying the main and auxiliary motors and the switch controlling the latter, this machine being shorter for a given length of hole than the previous machine. The driving and feed mechanism for the drill is similar to that of the parent Specification with a main spindle-driving motor M1 rotating the drill 115, Fig. 2, through gearing 110- 112, and also rotating, through gearing 111, 116, a feed-screw 117. An auxiliary reversible motor M2 drives through gearing 121, 122, a feed nut 123, the feed movement being dependent upon the relative rotation between the nut and screw; and, on reverse rotation of the nut, giving a quick return. The housing 101 for the driving mechanism is slidably mounted on a pair of cylindrical guides 103, Fig. 3, supported at the rear end in a conventional assembly (not described), for drilling a number of holes in a rock &c. face. The guides are spaced apart by brace members 104, 105, and the feed screw 117 is supported along the centre line. The brace 105 also carries a guide member for the drill, Fig. 5, comprising halfbearings 127, 128, hinged about pins 131, 132, respectively, and brought into line by a stop 134 when a clamping-nut 138 is tightened. Spring buffers 108 are provided at the front end of the guides and a stop 167 operates a switch on the housing 101 to disconnect the main circuit to the motors. A similar stop 168 actuates another switch having the same effect in the reverse or return movement. Electrical control. The control circuit, Fig. 7, comprises supply lines 140 passing through a mains switch 144 operated by a coil 145 from a press-button switch 150. The latter is interconnected as described below with a switch 147 for the main motor M1, while the auxiliary reversible motor M2 is controlled by a reversing switch 149 which is in turn interconnected with a switch 153 which by-passes either the switch 151 or 152 according to whether it is in the L.H. or R.H. positions, respectively. Switches 151, 152, in the control circuit are the end-of-run switches referred to above which serve to stop the motors when the machine reaches the end of its forward or return run. Interconnection between the push-button switch 150, Fig. 8, and the switch 147 for the main motor is effected by an arm 165, secured to the button 150a and guided between lugs 166, engaging a groove 157 in the hand-control knob 156. The switch 147 is biased by a spring 155 into the " off " position shown, a break 160 in the rim 159 allowing the push-button to return in this position. To switch the mains motor " in," the control knob 156 is turned clockwise slightly beyond its normal " on " position, whereupon the button 150a may be pressed to close the mains switch, arm 165 passing through a gap 161. The knob 156 is then allowed to rotate slightly in the opposite direction and arm 165 is trapped in a recess 162 so that both switches are held " on."